Conventionally, there is widely known, as a surface fastener including a base fabric made of cloth, a fabric surface fastener consisting of a hook surface fastener (A) including hook-like engagement elements made of a monofilament yarn on a surface of a base fabric, and a loop surface fastener (B) including loop-like engagement elements made of a multifilament yarn on a surface of a base fabric, wherein the loop-like engagement elements are engageable with the hook-like engagement elements. The surface fasteners are packed in bags and sold in the market in a state that the hook surface fastener (A) and the loop surface fastener (B) are engaged with each other. The surface fasteners are widely used in many fields such as garments, shoes, caps/hats, belts, supporters, pillow covers, luggage/bags, blood pressure manometers, commodity goods, binding tapes, packing materials, materials for civil engineering and construction, materials for agricultural and fishing industries, and toys.
Generally, the hook surface fastener (A) and the loop surface fastener (B) are respectively manufactured by the following method. Specifically, in manufacturing a base fabric 1 consisting of a ground warp yarn 3 and a ground weft yarn 2, the hook surface fastener (A) is manufactured by weaving a monofilament yarn 6 for hook-like engagement elements 5 into a base fabric 1 in parallel to a ground warp yarn 3, locally forming loops of the monofilament yarn 6 on the base fabric 1, thermally fixing the loop shape, and cutting leg portions of loops to form hook-like engagement elements 5; and the loop surface fastener (B) is manufactured by weaving a multifilament yarn 7 for loop-like engagement elements 4 into a base fabric 1 in parallel to a ground weft yarn 2, and locally forming loops of the multifilament yarn 7 on the base fabric 1 to form loop-like engagement elements 4.
As described above, the hook surface fastener (A) or the loop surface fastener (B) is mainly consisting of a ground warp yarn, a ground weft yarn, and a monofilament yarn for hook-like engagement elements or a multifilament yarn for loop-like engagement elements. Conventionally, as the ground warp yarn, the ground weft yarn, the monofilament yarn for hook-like engagement elements, and the multifilament yarn for loop-like engagement elements, fibers made of polyamide polymer such as Nylon 6, Nylon 66, Nylon 610, or copolymer containing these compounds as a main component are generally used. When polyamide fibers are used, however, the base fabric may be deformed by water absorption, moisture absorption, or heat. In some cases, the base fabric may have a wavy appearance by moisture absorption, water absorption, or heat. Thus, the appearance of the base fabric may be impaired. As a result, the quality of a product attached with a surface fastener may be impaired or degraded. Further, an intended large engaging strength, which is a most important factor of a surface fastener, may not be obtained.
Nowadays, most of the garments are manufactured using polyester fibers. When a surface fastener to be attached to the garments is made of polyamide, it is extremely difficult to simultaneously dye the garments and the surface fastener with the same color in the same dyeing condition, because the dyeabilities of the garments and the surface fastener are completely different. In order to match the color tones between the garments and the surface fastener, it is necessary to prepare a stock of a large number of surface fasteners having the color tones of final products.
As a technique for eliminating the aforementioned drawbacks involved when polyamide fibers are used, in recent years, there is proposal to use fibers made of polyester polymer such as polyethylene terephthalate or polybutylene terephthalate having low water absorbency/moisture absorbency, or copolymer containing these compounds as a main component. There are some documents describing use of polyester fibers for a surface fastener.
For instance, Patent Literature 1 describes using, as engagement elements composing a surface fastener, and fibers composing a woven/knitted fabric including the engagement elements, it is possible to use synthetic fibers made of polyester polymer such as polyethylene terephthalate (hereinafter, abbreviated as PET), polybutylene terephthalate (hereinafter, abbreviated as PBT), or copolymer containing these compounds as a main component, in addition to synthetic fibers made of polyamide polymer such as Nylon 6, Nylon 66, or Nylon 610.
Further, Patent Literature 2 describes it is possible to use fibers made of polyesters such as PET or PBT as fibers composing a base fabric of a surface fastener in addition to fibers made of polyamides such as Nylon 6 or Nylon 66, and it is preferable to use a nylon or polyester monofilament yarn for hook-like engagement elements, and a nylon or polyester multifilament yarn for loop-like engagement elements.
It is true that use of PET polyester fibers for a hook surface fastener or for a loop surface fastener makes it possible to eliminate a drawback involved when polyamide fibers are used i.e. a drawback that a surface fastener has a wavy appearance by water absorption, moisture absorption, or heat; and a drawback that it is necessary to prepare a stock of a large number of surface fasteners of many color tones because the surface fasteners are made of the same polyester as the primary fibers composing modern garments and have a difference in dyeability with respect to the garments. On the other hand, when a monofilament yarn made of PET polyester is used for hook-like engagement elements of a hook surface fastener, loop-like engagement elements are likely to be cut because the hook-like engagement elements are too hard. Further, when an instantaneous load i.e. impact by repeated peeling is generated because of hardness of hook-like engagement elements, the hooks are extensively deformed, and it is difficult to restore the shape of the hook-like engagement elements. Further, when a multifilament yarn made of PET polyester is used as a yarn for loop-like engagement elements of a loop surface fastener, the multifilament yarn forming loops is not easily loosened, and loops are likely to be flattened by repeated peeling. Thus, the engaging strength and engagement durability may be lowered, and in sewing a surface fastener, when an engagement element falls by a sewing thread, the engagement element may not rise even after the sewing thread passes the portion where the engagement element falls. Further, since the engagement element is hard, the wearer may feel the surface fastener hard. Thus, the surface fastener may not be appropriate for articles such as garments and commodity goods in which a soft touch is required.
Further, when a multifilament yarn made of PBT polyester is used as a yarn for loop-like engagement elements of a loop surface fastener, if the loop density is high, a space for engagement may be narrowed because the multifilament yarn is likely to loosen. As a result, the loop-like engagement elements may interfere with each other, and it may be difficult for the loop-like engagement elements to engage with the hook-like engagement elements. Thus, it is necessary to secure a space for engagement by raising. Further, when a monofilament yarn made of PBT polyester is used for hook-like engagement elements of a hook surface fastener, even if the hook-like engagement elements are engaged with loops, the hook-like engagement elements may be extended and may be disengaged from the loops because the yarn is soft and has a low tensile strength.
An object of the invention is to eliminate the drawbacks of a surface fastener using polyamide fibers i.e. the surface fastener may be deformed by water absorption, moisture absorption, or heat, and it is necessary to prepare a stock of a large number of products of many colors, taking into consideration a difference in dyeability; and to eliminate the drawbacks of a surface fastener using PET fibers i.e. a hard touch by hard engagement elements, and lowering of the engaging strength and engagement durability because it is difficult to rise the fallen engagement elements, the hook-shape of hook-like engagement elements is likely to extend, loop-like engagement elements are likely to be cut and flattened, and loop-like engagement elements are not easily loosened. Another object of the invention is to eliminate a drawback involved when PBT fibers are used i.e. the engaging strength is low.